Present invention relates to a registration/search system for image data in an electronic file device connected to a computer aided design (CAD) device and, particularly, to such system capable of extending an image on a sheet produced by the CAD and having a plurality of attributes into a plurality of image planes attribute by attribute so that image data can be displayed at high speed in an easily searchable manner.
The CAD device has been used widely in preparation of drawings. In the CAD device, a drawing is prepared by inputting different kinds of graphic elements constituting the drawing and then inputting, thereto, positional relations therebetween by means of a pointing device such as tablet or mouse. Data concerning the drawing inputted is usually referred to as drawing data or vector data and includes data related to the kind of graphic elements and data of positions thereof in a certain coordinate system, which are stored in a memory.
In order to display such drawing data stored in the memory, the data is extended into a plane by such means as a drawing processor, that is, the drawing data is converted into image data which is stored in a display memory device. Such image data is referred to as raster data. The drawing processor converts coordinates which are a portion of the drawing data, calculates an address of the display memory device corresponding thereto, decodes the kind of data and draw the decoded data in the calculated address. Data concerning the kind of image elements includes attributes each being information defining one of a plurality of different display properties of the drawing including contour information such as straight line and/or circular line and information concerning the kind of line, i.e., solid line or dotted line, line width and color, etc.
In storing the drawing data in the memory, it is divided into logic units called segments. For example, when a drawing showing a layout of an office room is to be prepared, a group of drawing data which concerns items such as a desk and a chair which can be considered as a unit is assigned to a different segment and the coordinate-conversion of a plurality of such groups is performed segment by segment, so that the desk and the chair can be moved arbitrarily as a unit. Further, by deleting drawing data segment by segment or stopping drawing procedure, chairs, etc., can be erased easily.
For a display of a complicated drawing, only portions thereof bearing necessary information can be displayed by erasing the remaining portions of the complicated drawing.
An example of such device is disclosed in Japanese Patent Application Laid-Open No. 62-205423.
The electronic file device is one of office automation (OA) devices developed recently. The electronic file device serves to scan an original image, convert data obtained by scanning into image data and store it in an optical disk provided therein. It also serves to read and display the stored data on demand.
In the electronic file device, in order to increase the number of drawing sheets that can be stored in the optical disk, image data is coded to compress data amount. This compression procedure is referred to as coding process or compression process and data processed thereby is referred to as coded data. When coded data is derived from the optical disk for display, coded data is decoded to recover the image data. This decoding process is referred to as an extension process.
A typical coding/decoding system is a Modified Huffman (MH) system, a Modified READ (MR) system or a Modified MR (MMR) system, which is used in a facsimile device. In each of such systems, image data is handled as a mere series combination of white pixels and black pixels. In coding, the image data is inputted thereto starting at either end of the pixel series and converted into a coded data and, in decoding, the coded data is decoded to the image data from either end of the pixel series to output pixels.
An example of the electronic file device is disclosed in Japanese Patent Application Laid-Open No. 62-243067 and an example of the coding system is disclosed in Japanese Patent Application Laid-Open No. 59-126368.
Among the conventional techniques mentioned above, the CAD device can provide a very easily understandable display of a complicated drawing since it is possible to display only drawing data or segments thereof which belong to attributes required by an operator so that only necessary information of the complicated drawing is obtained. However, since it is necessary, in displaying, to deciphor various attributes of the drawing data and to perform a coordinate calculation, it takes a relatively long time until a display of one image is completed.
On the other hand, in the conventional electronic file device, the processing of data in displaying a drawing comprises a coded data decoding step and a decoded data conversion step which are simple in nature and the whole image is enough to be scanned once. Therefore, a high speed display is possible. However, since the content of image is not divided into segments each having inherent meaning and it is impossible to select only necessary image information, a whole image is displayed, causing search thereof to be difficult. Particularly, in a case of search while watching a plurality of images in succession, the search speed is much reduced since it takes long time to pick-up only necessary portions of each of the images displayed successively.